Trends in Hospitalisations for Vaccine Preventable Respiratory Infections Following Emergency Department Presentations in New South Wales, Australia, 2012–2022

Background

Vaccine-preventable respiratory infections impact on healthcare systems globally. Despite availability of vaccines, fluctuations in vaccination rates, pathogen virulence and community transmission dynamics mean that these respiratory infections continue to pose substantial public health risks. To understand trends in vaccine-preventable respiratory infections, we analysed linked data from emergency department (ED), hospitalisations and deaths in New South Wales, Australia, from 2012 to 2022.

Methods

ED presentations with respiratory infection like illness were linked to hospitalisation and death records. Age-standardised rates of ED presentations, proportions subsequently hospitalised for acute respiratory infection (ARI) and specific vaccine-preventable disease diagnoses and 28-day mortality rates were estimated by year and age.

Results

From 2012 to 2022, there were 3,127,090 ARI-like ED presentations. Age-standardised rates increased until 2020, declined in 2021 and rebounded in 2022. Across all years, of these ARI-like ED presentations, 16.6% were hospitalised for acute respiratory infections, including pneumonia (7.9%), influenza (1.1%), RSV disease (1.3%), COVID-19 (0.8%) and pneumococcal disease (0.3%). Proportions hospitalised were highest in those aged 65+ years, except for RSV, which was highest in children aged 0–4 years. The highest 28-day mortality post-ARI-like ED presentation was observed with COVID-19 in adults aged 65+ years at 13.1%.

Conclusions

This study highlights the continuing burden of vaccine-preventable respiratory infections on an Australian healthcare system. These data can be used to monitor the effectiveness of vaccination programmes and other public health interventions. Future efforts should focus on enhancing surveillance and data linkage to improve precision and guide targeted public health strategies.